Use Form1 to create injection mold for benchtop injection molding machine


#1

Hi,

I wonder whether anyone in this forum has actually used the Form1 to create an injection mold that can be used for benchtop injection molding machines like Galomb, Tech Kits and the likes.

If you have done so have you used the resin molds alone or did you put it in some kind of aluminium master mold? How does the resin withstand the heat from the molten injected plastic and how many runs could you do with one mold?

Thanks for your help.

Bernd


#2

I have printed a small pineapple charm using the grey resin, made a rubber mold out of it (vulcanized rubber mold) and then injected with wax and casted in silver. The detail remained and it came out great.

I would not print the mold itself using the form1. You will never achieve the level of detail of the aluminum molds either, so I don’t see the point.


#3

Thanks for your comment.

From my point of view it makes perfectly sense to think about printing injection molds for a couple of reasons:

  1. cheap way to go from digital to real world injection molded object - cheapest simple aluminium mold will cost around 400 USD more sophisticated mold even more

  2. fast way to create injection molding objects (one day work for the mold)

  3. quick improvement and turn around time for design iteration

  4. very efficient for small runs of up to 100 objects - make the printer pay for itself

  5. Make use of an existing injection mold in a easy way

And quality wise if the Form 1 can print out a detailed pineapple charm as master for a rubber mold if should be able to the same for a pineapple mold as it is only the inverted form of a pineapple or any other object. --> I need to say that I do not dream of creating a mold for detailed action figures or any this like this therefore the quality  should be more than sufficient.

For further reference I suggest this white paper from Stratasys to have a deeper dive into the idea

http://www.stratasys.com/resources/~/media/B828788EF394436DB11BEB5209B2D22C.pdf

Additional question now is if the melting point of the Formlabs resin is above or equal 400 degrees Fahrenheit.


#4

This point

  1. Make use of an existing injection mold in a easy way

must read

  1. Make use of an existing bench top injection molder in an easy way

Sorry!


#6

Hi @PlasticLabs - this is definitely an application we’re interested in and it’s definitely possible to some extent with our current standard resins. For a nice example, check out this great video about Stickybones who are already successfully printing injection molds in our Black resin. Stickybones Video.

To your question about whether you can print the molds alone or whether you need an aluminium master, depending on your needs you can probably get away with printing the entire mold but a) if it is at 25 microns it’s going to take longer and b) if you’re experimenting and something was to go wrong it’s probably safer to encase it in an aluminium master mold. So I’d suggest printing the mold to fit an aluminium master case if possible. You can source these pretty easily online.


#7

Hi everyone,

this is something that I knew people had been doing and we’d been meaning to prove out for some time. I’m excited to share a white paper that documents injection molding from 3D printing molds using a desktop injectino molder from Galomb - producing 25 shots of LDPE parts.

^^ access the whitepaper here and I’m happy to answer any questions you have if this is an application you’re interested in.

Thanks!


#8

@JenniferMilne Would it be possible to share the file for the aluminium master mold used in the white paper?
We are experimenting with high temp resin and an injection molding machine.


#9

In one example we were working with a fairly old desktop molder and I pulled a favor and had a metal shop CNC mill us the aluminium frame. Depending on your machine you may want a custom sized frame as you need to be able to set the injector nozzle tightly against the hole at the top of the frame. However, many of the newer desktop molders are sold with blanks or empty frames for example see these stock molds. You might be able to find something online that suits your needs, but it does depend on your molder. I’m afraid I don’t have a file to hand, I just sketched out dimensions for the machinist.


#10

the big question is the structuring temp of the plastic you intend to inject- if its lower than the specification for High temp resin, then you should be able to inject into a printed mold.

But that is not your only concern.

The other is compatibility of the resin and the plastic you inject. For example- Polyethylene and Polypropylene are usually rotocast in aluminum molds, because they release more readily from aluminum than they do from steel.

Vinyl, on the other hand releases cleanest from nickle… and so molds are made of high nickle stainless, or are plated with nickle for a better release.

A printed resin tool might well bond to your molten plastic… or stick pretty well… so you might have to test first to determine if its an issue… and if it is, if there is a way to treat or seal the surface of the printed resin to prevent adhesion.

it is possible, for example- to print a tool and then paint it with a conductive paint… then simply electroplate a very thin coat of copper, and then a thin coat of nickle onto the surface. Mating surfaces either would have to be designed for a small play- or you would have to mask the mating surface to prevent the plating from covering that surface.